[Non-palpable lesions of the breast. Retrospective analysis of mammographic and ultrasonographic indications for surgery].

Introduction: The differential diagnosis of malignancy in small foci of microcalcifications or in extremely small nodes can be difficult. We carried out a retrospective analysis of integrated mammographic and US results, correlated with histologic data, to assess the limitations of each method and to optimize and benign/malignant ratio.

Materials And Methods: Our series consisted of 485 nonpalpable breast lesions submitted to histologic examination after vegetable charcoal marking. We gave each lesion an 0-5 score according to the degree of diagnostic doubt/suspicion after mammography and US, which results were correlated with histologic data to assess the carcinoma frequency in the various groups identified.

Results: The analysis of mammographic and US images showed that the most frequent mammographic alteration in the lesions submitted to biopsy was an isolated cluster of microcalcifications (40.99%): of these, 36.86% were neoplastic. The nodules submitted to biopsy, which were 29.81% of the total, showed a cancer rate (36.80%) very similar to that of the microcalcifications. The carcinoma rate rose to 37.93% when the microcalcifications were associated with nodes. The highest carcinoma rates, i.e., 52.94% and 66.66%, respectively, were found in parenchymal distortions, either isolated or associated with microcalcifications, which however were only 7.03% and 3.10%, respectively, of the total number of cases.

Discussion And Conclusions: Our study showed that: 1) a highly suspicious US result must be seriously considered when a negative mammography has poor intrinsic contrast; 2) a highly suspicious US image with a little suspicious good contrast mammography requires further confirmation before surgery is planned; 3) when the mammographic finding is mid-to-highly suspicious, further investigations are needed even if US is negative. To conclude, even though the histologic examination of nonpalpable breast lesions involves performing a biopsy, we believe this is acceptable when performed on an outpatient basis, under local anesthesia and removing a limited amount of tissue only. The benign/malignant ratio ranges 2 to 1.5: if it is further reduced (below 1.5), there will be the risk of missing some early neoplastic lesions.